The American Society of Clinical Oncology (ASCO) breast cancer follow-up guideline has not been updated since 2013.¹ In the interim, the survivor population has grown, the oncology workforce hasn’t kept pace, and clinicians have had little evidence-based direction on how to properly surveil a patient’s actual recurrence risk. ASCO’s Expert Panel took on that gap in this update, built primarily on a formal modified Delphi consensus process rather than a deep well of new randomized data.

Here’s what’s new and what it means for practice.

1. Follow-up is Now Explicitly Risk-Stratified

Instead of a uniform follow-up calendar, the guideline sorts patients into low-, intermediate-, or high-intensity surveillance groups based on stage, receptor/subtype, treatment response, and whether they are still on active systemic therapy. The goal is to match visit frequency and testing intensity to a patient’s actual risk of local, regional, or distant recurrence, and to free up oncology capacity for patients who need it most.

2. The 3 Intensity Tiers

The Expert Panel didn’t have randomized control trial (RCT) data to tell it exactly where to draw these lines, so the tiers themselves were built through the same modified Delphi consensus process as the rest of the guideline. These were drafted by the panel and rated by a 33-member consensus group across 3 rounds of voting until each definition cleared 75% agreement. The result is less a bright-line risk calculator than a practical sorting rule clinicians can apply today organized around the 2 factors that drove the most disagreement in that voting process: how far out from diagnosis a patient is, and whether they’re still on active treatment.

Low-intensity: Ductal carcinoma in situ off endocrine therapy, stage I hormone receptor–positive disease off all systemic therapy, or triple-negative breast cancer (TNBC)/HER2-positive disease at 5 or more years from diagnosis. Annual clinical visits (in person or virtual) occur via survivorship clinics, APPs, or primary care and include an annual mammogram for the first 3 years after the completion of treatment.

Intermediate-intensity: Stage I TNBC/HER2-positive disease within 5 years from diagnosis, stage II to III TNBC/HER2-positive disease with pathologic complete response after neoadjuvant therapy, or anyone on ongoing endocrine therapy. Oncology or survivorship-clinic visits should occur every 6 to 12 months for up to 10 years before transitioning to low-intensity.

High-intensity: TNBC with residual disease after neoadjuvant chemotherapy and fewer than 5 years from diagnosis, active systemic therapy, germline mutation carriers, inflammatory breast cancer, or hormone receptor–positive disease on a CDK4/6 inhibitor. Oncology visits should take place every 3 to 6 months for up to 10 years, with the potential to transition into the low-intensity group.

Tier assignment, not diagnosis or stage alone, is what should now drive the visit schedule and mammography interval discussed below, which is why the guideline frames intensity as the organizing concept for everything that follows.

3. Mammography Frequency

Mammography remains the mainstay of post-treatment imaging in every tier, but how often a patient gets one is no longer automatic. Patients who had breast-conserving surgery get annual mammograms for the first 3 years. After that, patients 50 or older with low-risk features (T1, low-grade, node-negative, estrogen receptor (ER)–positive, recurrence-free at 3 years) can move to mammography every 1 to 2 years. Patients under 50 or with TNBC/HER2-positive disease should stay on annual surveillance mammography. Continued annual mammography remains an option for any patient who prefers it after a risk/benefit discussion.

4. The Mammo-50 Trial

The UK’s phase 3 Mammo-50 noninferiority RCT (5235 women, median follow-up of 5.7 years) is part of the basis for de-escalating mammography. Less-frequent mammography (biennial after breast-conserving surgery, triennial after mastectomy) was noninferior to annual mammography for 5-year breast cancer–specific survival, overall survival, and recurrence-free interval, and a companion quality-of-life analysis showed no difference in distress, worry, or fear of recurrence between arms. Of note, the Expert Panel risk-stratified these findings from the low-intensity group.

5. Utilizing Routine Blood Tests and Tumor Markers for Decision Making

ASCO has advised against routine surveillance blood work since its 2006 and 2013 updates, but the panel restated it because the practice persists anyway. Complete blood counts, chemistry panels, and the tumor markers CEA, CA 15-3, and CA 27.29 remain discouraged for asymptomatic patients. No evidence currently shows that these tests catch recurrence earlier than clinical symptoms would, or that catching it earlier through blood work improves survival. What they reliably do add is false-positive results, follow-up testing, and patient anxiety, all without a proven benefit. The guidelines note this is a rapidly evolving area, and the recommendations will be updated with any new data in the future.

6. ctDNA as Routine Surveillance

The panel adapted language from ASCO’s ctDNA Testing in Solid Tumors and Lymphoma guideline that fractional/percentage/concentration-based ctDNA or cfDNA measures cannot be recommended in any specific context for recurrence monitoring outside a clinical trial.² The evidence shows ctDNA has clinical validity (detectable ctDNA correlates with worse outcomes, hazard ratios as high as 25.1 for postsurgical detection in 1 cohort study), but no prospective trial has yet shown clinical utility or that acting on a ctDNA result improves outcomes.³ Several trials (DARE [NCT04567420], CATE [NCT06923527], LEADER [NCT03285412], CIPHER [NCT05333874], EXACTDNA003 [NCT06401421], SIGNAL-ER 101 [NCT07214532]) are underway to answer that question.

7. Supplemental MRI is a Shared Decision

MRI may be offered on top of mammography for a defined set of higher-risk patients such as known or untested germline mutation carriers (BRCA1/2, PTEN, STK11, TP53, and others) with intact breast tissue, and patients with prior radiation exposure to breast tissue between ages 10 to 30. Additional factors that can tip the decision toward supplemental MRI include age under 50 years old at diagnosis, invasive lobular histology, a primary cancer diagnosed within 12 months of a negative mammogram or missed on mammogram, or extremely dense breasts. Contrast-enhanced mammography or ultrasound are acceptable alternatives when MRI is contraindicated or unavailable.

8. Routine Imaging for Distant Metastases

The guideline shows a 97% consensus agreement for not imaging patients who are asymptomatic. Routine bone scans, chest radiographs, liver ultrasounds, CT, and FDG-PET are not recommended in asymptomatic patients with no exam findings. The panel’s reasoning tracks the same cost-benefit logic that runs through the rest of the guideline; these scans generate false positives that trigger further invasive work-up, expose patients to unnecessary radiation, and add to the financial hardship that already affects a large share of breast cancer survivors for years after treatment ends, all without evidence that earlier detection through routine imaging changes outcomes. That guidance doesn’t extend to new or persistent symptoms, though; bone pain, abdominal pain, dyspnea, chest pain, persistent headache, or vision changes still warrant prompt work-up regardless of how long it has been since diagnosis.

9. Conducting Follow-Up

Given a projected US oncology workforce that will meet only 29% of patient needs by 2037, the guideline explicitly endorses shifting lower-risk, low-intensity follow-up to survivorship clinics, APPs, and primary care, reserving oncology-team visits for intermediate- and high-intensity patients. The panel frames this the same way as tailoring surgery or chemotherapy intensity: not a reduction in care, but a better match of resources to risk. It also flags real access and equity concerns to keep in mind while making that shift, including documented racial and insurance-related disparities in patients who currently receive surveillance mammography and MRI and the financial toxicity of ongoing surveillance itself.

Reference

1. Nahleh Z, Alfano CM, Somerfield MR, et al. Breast cancer follow-up and surveillance after primary treatment: ASCO guideline update. J Clin Oncol. Published online July 16, 2026. doi:10.1200/JCO-26-01700.
2. Lockwood CM, Messersmith HJ, Kim AS, et al. Circulating tumor DNA Testing in solid tumors and lymphoma: ASCO guideline. JCO Oncol Pract. Published online June 18, 2026. doi:10.1200/OP-26-00311
3. Garcia-Murillas I, Schiavon G, Weigelt B, et al. Mutation tracking in circulating tumor DNA predicts relapse in early breast cancer. Sci Transl Med. 2015;7(302):302ra133. doi:10.1126/scitranslmed.aab0021